899  
FXUS65 KBYZ 260912  
AFDBYZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BILLINGS MT  
212 AM MST FRI FEB 26 2021  
   
DISCUSSION
 
 
TODAY THROUGH SATURDAY...  
 
CURRENT UPPER AIR ANALYSIS SHOWS BROAD TROFFING OVER THE REGION  
WITH A 110KT H3 JET NOSING THRU THE PACIFIC NW. SW WINDS IN THE  
GAP AREAS ARE SOMEWHAT MODEST WITH PEAKS IN THE 40S, AS WINDS SEEM  
AFFECTED BY THE INSTABILITY IN PLACE. THERE IS A SHORT OPPORTUNITY  
FOR MID LEVEL WARM ADVECTION WHICH SHOULD ALLOW FOR SOME INCREASE  
IN GAP FLOW A BIT LATER THIS MORNING, BUT BY MIDDAY THE MIXING  
SHOULD PUT AN END TO ANY ADVISORY LEVEL GUSTS. REGARDING BIG  
TIMBER AND HARLOWTON, WINDS ARE GUSTING IN THE 20S AND 30S, BUT  
WILL CERTAINLY INCREASE WITH THE ONSET OF POST-SUNRISE MIXING.  
MID LEVEL FLOW IS QUITE BORDERLINE FOR WARNING LEVEL WINDS, BUT  
LOOKS LIKE A GOOD CHANCE OF 50+ MPH GUSTS. WILL LEAVE ALL  
HIGHLIGHTS AS IS.  
 
OUR WESTERN MOUNTAINS WILL SEE SEVERAL INCHES OF SNOW (5-10")  
TODAY AND TONIGHT, COURTESY OF THE MOIST AND UNSTABLE PACIFIC  
FLOW. SNOWFALL WILL BECOME MORE SHOWERY BY SATURDAY BEHIND THE  
SHORTWAVE IN A VEERED NW FLOW.  
 
DOWNSLOPE FLOW WILL KEEP OUR LOWER ELEVATIONS DRY WITH TEMPS IN  
THE UPPER 30S TO MID 40S TODAY. BY THIS AFTERNOON WE SHOULD SEE  
SOME INSTABILITY-DRIVEN RAIN/SNOW SHOWERS BEGIN TO SPREAD OFF THE  
MOUNTAINS. LOWER ELEVATION SNOW POTENTIAL GETS MORE INTERESTING  
LATE TONIGHT AND SATURDAY AS A CANADIAN COLD FRONT SAGS INTO THE  
AREA. THE COMBINATION OF WEAK SYNOPTIC SCALE FORCING WITH STEEP  
MID LEVEL LAPSE RATES AND POSSIBLE CONVERGENCE ALONG A SURFACE  
FRONT SUGGESTS THE POSSIBILITY OF HEAVIER BANDED SNOW SHOWERS  
ESPECIALLY OVER OUR WEST AND CENTRAL PARTS. MUST STRESS  
UNCERTAINTY IN THE TIMING AND LOCATION OF THE FRONT ITSELF (THE  
GFS BRINGS IT IN SOONER AND IS COLDER THAN OTHER MODELS). AS WAVE  
PASSES THRU WY TOMORROW, THERE ALSO LOOKS TO BE A BRIEF PERIOD OF  
STRONGER FORCING AND UPSLOPE FOR THE EAST SIDE OF THE BIGHORNS...  
AND COULD SEE A QUICK COUPLE INCHES OF SNOW IN AND AROUND  
SHERIDAN. HEADS UP TO ANY SATURDAY MORNING TRAVELERS SOUTH OF  
BILLINGS ON I-90.  
 
FOR BILLINGS ITSELF, WE WILL LIKELY SEE SOME SNOW SHOWERS LATE  
TONIGHT AND SATURDAY, AND SURFACE TEMPS WILL TURN COLD ENOUGH TO  
ALLOW SOME SNOW TO STICK, BUT ANY REAL ACCUMULATION POTENTIAL WILL  
BE DEPENDENT ON LOCATION OF SNOW BANDS. ENSEMBLES SUGGEST 0.5-1.0"  
OF SNOW AT BILLINGS AND THIS IS A GOOD FORECAST AT THIS TIME.  
 
JKL  
 
SATURDAY NIGHT THROUGH FRIDAY...  
 
A FEW SNOW SHOWERS WILL LINGER OVER THE WEST SATURDAY EVENING,  
BEFORE DRIER CONDITIONS MOVE INTO THE AREA FOR SUNDAY AS HIGH  
PRESSURE BUILDS IN FROM THE WEST. HIGH PRESSURE OVER THE AREA  
SUNDAY THROUGH MUCH OF THE WEEK WILL PROMOTE DRY CONDITIONS,  
MODERATING TEMPERATURES, AND PERIODS OF GUSTY WINDS ALONG THE  
WESTERN FOOTHILLS. SUNDAY THROUGH TUESDAY LOOKS TO BE THE  
WINDIEST, ALTHOUGH JUST BELOW HIGHLITE LEVELS AT THIS TIME.  
TUESDAY INTO WEDNESDAY, A SPLITTING WAVE IS PROGGED TO MOVE ACROSS  
THE REGION, BUT AT THE MOMENT IT LOOKS LIKE THIS WAVE WILL BE  
FAIRLY DRY.  
 
TEMPERATURES MODERATE SUNDAY THROUGH FRIDAY WITH HIGHS IN THE 40S  
AND 50S. LOW TEMPERATURES IN THE 20S ARE FORECAST MOST NIGHTS. STP  
 

 
   
AVIATION
 
 
SW-W WINDS WILL REMAIN GUSTY ALONG THE WESTERN FOOTHILLS TODAY.  
EXPECT GUSTS OF 35-50 KNOTS AT KLVM-K6S0-KHWQ. WINDS WILL DECREASE  
TONIGHT. VFR FLIGHT CONDITIONS WILL PREVAIL AT LOWER ELEVATIONS  
TODAY, BUT THE POTENTIAL FOR SNOW SHOWERS AND MVFR/IFR CONDITIONS  
WILL INCREASE AS A CANADIAN COLD FRONT SAGS INTO THE REGION  
TONIGHT. MOUNTAINS WILL SEE PERSISTENT SNOW SHOWERS OVER THE NEXT  
24 HOURS, AND WILL STAY OBSCURED. JKL  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
TDY SAT SUN MON TUE WED THU  
-------------------------------------------------------  
BIL 042 021/030 017/040 025/047 028/044 025/046 028/050  
2/W 35/J 20/N 00/U 00/N 00/U 00/U  
LVM 036 019/030 013/036 021/043 024/038 022/042 024/046  
5/J 63/J 20/N 01/N 11/N 00/U 00/U  
HDN 044 019/030 014/042 021/050 026/047 023/049 024/053  
1/N 24/J 10/U 00/U 11/B 00/U 00/U  
MLS 043 017/028 015/041 024/052 028/047 024/050 026/053  
2/W 22/J 00/N 00/U 00/B 00/U 00/U  
4BQ 043 019/030 016/041 022/051 026/046 025/050 026/052  
1/N 22/J 10/U 00/U 00/B 00/U 00/U  
BHK 042 016/028 012/039 021/052 024/045 021/049 024/051  
1/N 21/E 10/N 00/U 00/B 00/U 00/U  
SHR 040 017/029 008/037 017/049 022/042 018/045 020/049  
1/B 36/J 20/U 00/U 11/B 10/U 00/U  
 

 
   
BYZ WATCHES/WARNINGS/ADVISORIES
 
 
MT...HIGH WIND WARNING IN EFFECT UNTIL 3 PM MST THIS AFTERNOON FOR  
ZONES 63-141-172-228.  
WIND ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR ZONES 65-66.  
WY...NONE.  
 

 
 

 
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